The exhaust system of an engine is generally situated toward the front of the engine compartment where the cooling fan is positioned, while the intake system is situated toward the dash panel that divides the driver's seat and engine compartment.
The intake system of an intake/exhaust reverse engine is, however, placed to face the cooling fan, while the exhaust system is placed toward the dash panel. Therefore, the cooling air blown from the cooling fan may not smoothly be delivered to various sensors (i.e., oxygen sensor, or the like), wiring harness of the sensors, catalytic converter, and the like that all constitute the exhaust system, thereby causing heat damage to primary components of the exhaust system. In particular, if the oxygen sensor directly affecting the discharge of the exhaust gas gets too hot, the amount of exhaust gas exceeds the reference value compared to that of the vehicle exhaust gas regulation.
Thus, some vehicles are formed with holes at their hoods to enable air to be circulated from the upper surface of the hood during vehicle motion to the periphery of the engine exhaust system. However, in such construction, the holes on the hood may degrade the appearance of the vehicle.